Fluid operated clutch



April 22, 1952 cqF. BALL FLUID OPERATED CLUTCH Filed Sept. 28, 1948 152.0672252?? /zaTZQfEa ZZ Patented Apr. 22 1952 FLUID OPERATED CLUTCH Charles F. Ball, Franklin, Pa., assgnor to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania `Aj'lplication September 28, 1948, Serial No. 51,587

8 Claims. l

This invention relates to a clutch, especially.

to a clutch with a predetermined maximum pressure applied to engagement thereof, in order that the torque applied to a driven member may be limited to a predetermined maximum.

There are numerous applications in which it is desirable to have a clutch of the torque limiting type. One such application is in mining machinery where one power source may serve the purpose of driving several different machines having different power requirements, and the available power may in some cases be much greater than is required to perform a particular function. In such cases, an application of excessive power might result in failure of the machine and corresponding failure of the function pcrformed or purpose served by the machine.

It is accordingly an object of this invention to provide a friction clutch of the torque limiting type in which a simple mechanism is provided which will insure that not more than a predetermined maximum amount of torque is transmitted. It is another object to provide a clutch which can be economically manufactured and in which the torque limiting features allow for adjustment of the maximum amount of torque which can be transmitted. These and other objects are accomplished in a torque limiting friction clutch in which the clutch engaging member travels through a xed distance at the end of which it strikes a shoulder which limits itstravel in the direction of clutch engagement.

VClutch plates are disposed between the clutch `a clutch embodying the invention;

Fig. 2 is a view in section substantially on the planes of line 2-2 of Fig. 1; and

Fig. 3 is a detail View of a portion of Fig. l showing the yieldable back-up member in a different operating position kfrom that which is shown in Fig. 1.

In the embodiment of the inventionshown in the drawing, power from any suitable power source, not shown, is supplied to the clutch by way of a shaft 2. A hub 4 is mounted on shaft 2 and is driven thereby by means of keys which cooperate with one or more keyways, such as those shown at 6.

Hub 4 has three axially extending projections 2 8 which are axially slotted or recessed to receive keys I0 which may, if desired, be welded to the hub as shown at I2.

The hub constitutes a rotatable element having a circumferential shoulder I4. A plate engaging member I6 is slidable on the rotatable element 4 in the direction of clutch engagement and is limited in its movement in that direction by engagement with the shoulder I4. A yieldable back-up member I8 is provided, in order that the clutch plates or discs disposed between the plate engaging member I6 and the back-up member may have a predetermined pressure applied for their engagement.

The yieldable back-up member comprises: a back-up plate 2l! having a plurality of recesses, one of which is shown at 22; a spring holder 24 having a similar number of recesses, one of which is shown at 28, the recesses 22 and 26 being opposed and being arranged in axial alinement; a plurality of springs, one spring 28 in each pair of opposed recesses 22 and 26; and a threaded connection 30 which has an inward extending flange 32 cooperating with an outward extending flange 34 on plate 20 to provide a lost motion connection therewith, and which has a threaded connection with the spring holder 24. Spring holder 24 is provided with at least one recess 35 which is threaded to receive a screw 36. 'Ihe screw 36 cooperates with one of a plurality of openings 38 in the threaded member 3U to permit holding the member 38 in a selected one of a plurality of differentV positions. This feature permits setting the clutch with a predetermined load on the springs 28.

Between the yieldable back-up member indicated generally at I8 and the plate engaging member I6, there are disposed alternate clutch discs or plates 40 and 42. Plates 48 are provided with outward-extending projections 44 which cooperate with axially extending grooves or recesses 46 in a housing 48, in order that plates 48 may be non-rotatable with regard to the housing. The intermediate alternate plates 42 are nonrotatable with regard to the hub 4 because of the aforesaid keys I0 which cooperate with recesses 5|) in the plates 42.

A cup-shaped end cap 52 is secured to one end of housing 48 by means of screws 5 4, and an end plate 58 is secured to the opposite end of housing 48 by means of screws 58. End plate 5B is provided with a hub 60 which is keyed to a sleeve 62 by means of a key 64. Sleeve 62 constitutes the output shaft and is rotatable on the input shaft 2 by means of the bushing or sleeve bearing 66.

Rotatable element 4 is provided with a plurality of openings to accommodate a similar number of clutch operating rods 68. The rods B8 are screwed at 69 into plate engaging member I6 and are provided at their other end with a reduced diameter portion l which engages a flange l2. The flange 'i2 is clamped in place on rods 6B by means of nuts one of which is shown aty 74. A spring te is preferably provided with. each clutch actuating rod 68 and is compressed between hub t and plate engaging member l5.

The aforesaid flange 12 is integral with a hydraulic cylinder 'i8 of which the piston 3B is secured to the end of shaft 2 by means of a nut 82. At its outer end the hydraulic cylinder i8 is provided with an integral connection 84 having a fluid passage 85 therethrough. A hydraulic chamber 38 is mounted on'the connection il@ in such a manner that connection te may rotate relative to the chamber B8. To this end, the inner race 9S of a ball bearing is clamped between a shoulder 92 and a snap ring il@ while the outer race SS is clamped between a plate 93 and a anged washer lEil by means of threaded members 62 extending through the chamber into the plate lit. Flanged washer it serves to supported a suitable oil seal to minimize the amount of hydraulic iiuid which may leal: past the bearing. A hydraulic fluid conduit ille has a threaded connection with the uld chamber S8 and supplies hydraulic fluid to the inside of the chamber by way of a passage ist in the chamber wall.

Operation The clutch is shown engaged in Fig. l. 3 the back-up member is shown with or lost motion being taken up betwen iiangc 3i ol plate Eil and lia-nge 32 of sleeve B. in order for the clutch parts to move from the position shown in Fig. l to the position shown in Fig, 3, the plate engaging member I5 must move to the left away from shoulder I4; it does this under the action of springs 23 and it. By the time the parts have taken the position shown in Fig. 3, the springs 2S have been extended or expanded as far Yas they can go, because of the two flanges 3?. and 34 coming into engagement. Further leftward movement of plate engaging member l@ has to be. accomplished by further extension or springs 13. n

With the clutch disengaged, if it'is desired to engage the clutch, hydraulic fluid is admitted to the interior of cylinder '-S by way or conduit l liti, passage H35 in the wall of chamber te and pase sage 86 through the connection 613. The iluid pressure moves the cylinder "i8 to the right as seen inFig. l. Flanges 'lthereupon move the'actuating rods 58 to the right as seen in Fig. 1 causing the plate engaging member I6 tov move to' the right and squeezing the clutch plates lil and 42 together.

The rst portion of the rightwardl travel oi' plate engaging member I6 takes up the slack betweenA the clutch platesY and partially compresses springs lt. Further movement to the right of the plate engaging member I6 will necessitate compressing the springs 28 in addition to iurthery compressing springs 78. Plate engaging member le can move to the right only until it comes up against shoulder I4 on the rotatable element d. The amount of pressure that is being applied to the engagement of the clutch plates is determined by the pressure exerted by springs 28, and this pressure is determined by the amount of initial compression put on the in the slacii 4 springs by means of the threaded sleeve 30, and by the amount by which the flange 34 is separated from iiange 32. This separation leaves a space between the two ilanges which is clearly seen in Fig. l.

With the clutch thus engaged, power is transmitted from input shaft 2 through rotatable element t, lreysr IB, clutch plates 42, clutch plates dil, housing IBS, housing plate 53 and output shaft or sleeve 62.

With a clutch made according to this invention, a predetermined amount of compression may be applied to the springs 28. This compression is easily varied or adjusted by removing the end cap 52 after which screw 36 may be turned inward far enough to permit rotation of sleeve 30 in the desired direction. The periphery of sleeve 3G may be provided with suitable indica which may be calibrated in terms of clutch pressure, torque, or in any other desired manner. When the sleeve 39 has been set to provide the desired pressure, screw 3e may be screwed outward in its tapped hole 35 to hold the sleeve in its-adjusted position. The clutch plates cannot thereafter be submitted to an indennita and unlimited pressure. The maximum pressure on the plates is reached when the shoulder i4 comes' into engagement with the plate engaging member as described above.

Thus the invention provides a clutch in which the plate engaging member moves through a fixed distance in engaging the clutch and in which the plates are compressed together under a predetermined maximum pressure, and the clutch will transmit only a maximum torque according to the maximum clutch pressure. Other advantages will be apparent tothose skilled in the art.

While there is in this application speciiically described one form which the invention may assume in practice, it will be understood that this form of the same is shownffor purposes of illustration, and that the invention may be modied and embodied in various other forms without departing from its spirit or the scope oi the appended claims.

What I claim as new and desire to secure by Letters Patent is:

l. In a uid operated clutch, a housing, a rotatable element, a shoulder on the element, e plate engaging member movable on the element and limited in its movement by the shoulder, a yieldable back-up member, clutch plates between the plate engaging member and the back-up member, alternate plates being non-rotatable relative to the housing and the intermediate alternate plates being non-rotatable; relative to the rotatable element, and spring-opposed` fluid operated means connected to eiect relative movement of the plate engaging member and the back-up member to engage and disengage the clutch within the limits imposed by the aforesaid shoulder onthe rotatable element.

2. The clutch of claim l, in which the yieldable back-up member comprises a plate provided with a plurality of recesses, a spring; holder having recesses opposed to the recesses of. saidlplate, a

spring in each` pair; or opposed. recesses, and a able back-up member, clutch plates between the plate engaging member and the back-up member, alternate plates being non-rotatable relative to the housing and the intermediate alternate plates being non-rotatable relative to the rotatable element, and a spring-opposed hydraulic piston and cylinder connected to effect relative movement of the plate engaging member and the back-up member to engage and disengage the clutch within the limits imposed by the aforesaid shculder on the rotatable element.

4. The clutch of claim 3, in which the yieldable back-up member comprises a plate provided with a plurality of recesses, a spring holder having recesses opposed to 'the recesses of said plate, a spring in each pair of opposed recesses, and a sleeve having a lost motion connection with one of said recessed parts and a threaded connection with the other.

5. The clutch of claim 4, and powered means connected to drive the rotatable element, the powered means including a shaft, the piston being secured to the end of the shaft, and the cylinder being movable on the piston and being connected to the plate engaging member.

6. The clutch of claim 3, and powered means connected to drive the rotatable element, the powered means including a shaft, the piston being secured to the end of the shaft, and the cylinder being movable on the piston and being connected to the plate engaging member.

CHARLES F. BALL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 865,450 Sturtevant Sept. 10, 1907 1,442,092 Parsons et al. Jan. 16, 1923 1,632,526 Willgoos June 14, 1927 2,946,453 Havill etal. July 7, 1936 2,089,733 Criley Aug. 10, 1937 2,120,798 Criley June 14, 1938 2,282,143 Carter May 5, 1942 2,336,220 Lawler et al Oct. 9, 1945 FOREIGN PATENTS Number Country Date 12,836 Great Britain May 31, 1912 583,658 Germany Aug. 24, 1933 

